System For Attaching A Tool To A Work Machine

ABSTRACT

A carrier is provided for releasably attaching a tool to the lift arms of a work machine. The carrier comprises a lift arm attachment point for attachment to the lift arm, a tool attachment point for releasable attachment of the tool to the carrier, and a contact pad, for contacting the tool in use. In use, the lift arm and contact pad lie in the same vertical plane. Providing a contact pad between the carrier and tool in line with the lift arm removes any transverse bending forces on the carrier.

FIELD OF THE INVENTION

The present invention relates to the attachment of tools to the liftarms of a loader or other work machine.

BACKGROUND OF THE INVENTION

Work machines, such as loaders, are used in many industries, such asfarming and construction, and are used to perform many different jobswithin each industry. For example, farmers use loaders to move soil aswell as lift hay bales and other heavy items. A single machine is ableto perform many different tasks by having different tools that can bereleasably attached to the loader lift arms. This means that the userneed not buy several machines, each dedicated to a particular task, butmay use one or a few, multipurpose machines instead. This clearly hasadvantages in terms of cost.

However, the task of attaching and detaching tools from loaders can bedifficult. The tools are typically heavy, weighing upwards of a coupleof hundred pounds, and manually maneuvering them is a physicallydemanding job. The means of attachment itself can also be cumbersome anddifficult to operate, particularly during periods of cold weather whenthe operator will be wearing heavy gloves.

Various arrangements have been proposed to address this problem. Forexample, U.S. Pat. No. 5,466,113 and U.S. Pat. No. 7,001,137 bothdisclose latching arrangements for locking a tool to the lift arms of awork machine.

U.S. Pat. No. 5,466,113 discloses the use of a carrier or support,pivotally coupled to the lift arms using a pin, the carrier includingtwo pairs of brackets for receiving an elongate, horizontal locking barthat is used to attach the tool to the carrier. The locking bar can bereciprocated along a horizontal axis between a locking position and anunlocking position. Corresponding brackets on the tool can be positionedin a space between the brackets on the carrier so that in the lockingposition the locking bar extends through the apertures in the bracketson both the carrier and the tool, thereby securing the tool to thecarrier. The elongate locking bar allows the tool to be simply detachedand attached to the carrier from one side only.

U.S. Pat. No. 7,001,137 discloses a similar system to that described inU.S. Pat. No. 5,466,113, but with a hydraulic cylinder for moving thelocking bar between the locked and unlocked positions.

These systems are effective and user friendly, but suffer from limiteddurability of the carrier when the carrier is subjected to significantloads in use.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved carrierarrangement for attaching a tool to the lift arms of a work machine,that offers the advantages of the prior art but also provides greaterdurability.

In a first aspect, the invention provides a combination including a liftarm, a tool and a carrier, the carrier coupled to the lift arm and thetool for releasably attaching the tool to the lift arm, the carriercomprising: a lift arm attachment point for attachment to the lift arm;a tool attachment point for releasable attachment of the tool to thecarrier; and, a contact pad, for contacting the tool in use; wherein, inuse, the lift arm and contact pad lie in the same vertical plane.

The lift arm attachment point may advantageously lie in the verticalplane. The tool attachment point may also advantageously lie in thevertical plane. The tool attachment point may form a part of the contactpad.

Providing a contact pad between the carrier and tool in line with thelift arm removes any transverse bending forces on the carrier. Forcesapplied to the tool by the lift arm during pushing operations passdirectly from the lift arm through the carrier to the tool withoutplacing any shear stresses on the carrier. Likewise, forces applied bythe tool to the carrier pass directly to the lift arms. This provides acarrier that allows the tool to be releasably attached to the lift arms,with great durability. Prior carrier arrangements of this type have beenfound prone to failure due to bending forces applied to the carrierduring use.

In a second aspect, the invention provides a carrier for attaching atool to a pair of lift arms of a work machine, comprising: right andleft lift arm attachment points, spaced from one another in a transversedirection, for attachment to the lift arms of a work machine; a toolattachment point for releasable attachment of the tool to the carrier;right and left contact pads, for contacting the tool in use; wherein theright lift arm attachment point and right contact pad lie in a firstplane perpendicular to the transverse direction and the left lift armattachment point and left contact pad lie in a second planeperpendicular to the transverse direction.

The carrier may further comprise a fastener for releasably securing thetool to the carrier at the tool attachment point.

The carrier may include right and left tool attachment points, and theright tool attachment point may lie in the first plane and the left toolattachment point may lie in the second plane. The tool attachment pointsmay be formed within the contact pads. The tool attachment points maycomprise a recess formed in each of the contact pads for receiving acorresponding bracket on a tool. The fastener may include a bar thatextends through bores formed in the contact pads.

The carrier may comprise a carrier frame and the contact pads may bewelded or otherwise fixed to the carrier frame. Alternatively, thecontact pads may be integral with a carrier frame. The carrier frame maycomprise a pair of parallel walls and the contact pads may extendbetween the parallel walls.

The lift arm attachment points preferably allow for pivotal movement ofthe carrier relative to the lift arms about a transverse axis.

The carrier may comprise right and left pairs of upright walls, and atransverse member connecting the right and left pairs of upright walls,wherein the right contact pad is positioned between the right pair ofupright walls and left contact pad is positioned between the left pairof upright walls. The right lift arm attachment point may be positionedbetween the right pair of upright walls and left lift arm attachmentpoint is positioned between the left pair of upright walls.

In a third aspect the invention provides combination including a liftarm, a tool and a carrier, the carrier coupled to the lift arm and thetool for releasably attaching the tool to the lift arm, the carriercomprising: a lift arm attachment point for attachment to the lift arm;a tool attachment point for releasable attachment to the tool; andwherein, in use, the lift arm and tool attachment point lie in the samevertical plane.

In a fourth aspect, the invention provides a carrier for attaching atool to a pair of lift arms of a work machine, comprising: right andleft lift arm attachment points, spaced from one another in a transversedirection, for attachment to the lift arms of a work machine; right andleft tool attachment points for releasable attachment of the tool to thecarrier; wherein the right lift arm attachment point and right toolattachment points lie in a first plane perpendicular to the transversedirection and the left lift arm attachment point and left toolattachment point lie in a second plane perpendicular to the transversedirection.

In a fifth aspect, the invention provides a method of attaching a toolto a lift arm of a work machine comprising the steps of: connecting thelift arm to a carrier at a first attachment point on the carrier; andconnecting the tool to the carrier at a second attachment point on thecarrier such that a contact pad on the carrier abuts the tool, the liftarm and contact pad lying in the same vertical plane.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiment will be described in detail below withreference to the accompanying drawings wherein:

FIG. 1 is a side view of the lift arms of a work machine, with a toolattached to the lift arms using a carrier in accordance with the presentinvention;

FIG. 2 is a detailed rear perspective view of the carrier attached tothe tool and to the lift arms, shown in FIG. 1;

FIG. 3 is a rear perspective view of the carrier and tool of FIGS. 1 and2, without the lift arms shown;

FIG. 4 a is a rear perspective view of the carrier of FIGS. 1 to 3;

FIG. 4 b is a front perspective view of the carrier of FIG. 4 a;

FIG. 4 c is a front view of the carrier of FIGS. 4 a and 4 b; and,

FIG. 5 is a rear respective view of the tool illustrated in FIGS. 1 to3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The term “work machine” as used herein means any vehicle used in theagricultural, construction or forestry industries for performing heavytasks. Example work machines are loaders and tractors.

The term “lift arm” as used herein covers any type of movable arm on awork machine to which a tool or implement can be attached. Lift arms aresometimes referred to as “booms”.

The term “tool” as used herein can mean any implement or attachment fora work machine, such as a bucket, pallet fork or bale spear.

The term “attachment point” as used herein refers to any mechanicalfeature that allows for attachment thereto, such as a hook, a ring, anaperture, a passageway, a lug, a bracket, a threaded bore or shaft, arecess, a shelf or shoulder.

The term “contact pad” as used herein means an element that provides anabutment surface through which force can be applied. It is not limitedin size or shape and can be discontinuous. It can be designed to fitagainst the surface of a particular tool or tools.

FIG. 1 is a side view of the lift arms 11 of a work machine connected toa tool 10 by a carrier 12 in accordance with the invention. Only one ofthe parallel lift arms 11 can be seen in the view of FIG. 1. The liftarm 11 is attached to the front side of an agricultural tractor or workmachine that is only partially shown. The work machine includes a mastor plate 13 to which the lift arm is pivotally attached so as to pivotabout a transverse or horizontal axis. The lift arm has two sections 11a and 11 b, pivotally joined about a horizontal pin and can be movedrelative to the work machine in a vertical plane. The hydraulic ram 14is operable to pivot the lift arm about its central joint.

Each lift arm is attached to the carrier at two points. A first lift armattachment point 16 is provided at the lower end of the carrier and asecond lift arm attachment point 17 is provided about midway up thecarrier. The carrier is pivotable about a horizontal axis passingthrough the attachment point 16 by movement of a second hydraulic ram15. This type of connection between lift arms and carrier is describedin U.S. Pat. No. 7,001,137, the contents of which are incorporatedherein by reference.

The tool, in this case a bucket 10, is attached to the carrier at twopoints. A hook 18 on the bucket engages a transverse bar 19 at the topof the carrier. A second attachment point 30 is provided at the bottomend of the bucket, as will be described in greater detail.

FIG. 2 shows the arrangement of the bucket 10, carrier 12 and lift arms11 in more detail. FIG. 2 is a rear perspective view of the attachmentof the lift arms to the bucket via the carrier. As can be seen in FIG.2, there are two lift arms 11 in a parallel, spaced apart relationship.

FIG. 3 is a rear perspective view showing just the bucket and thecarrier.

FIG. 4 a is front perspective view of the carrier alone, FIG. 4 b is arear perspective view of the carrier alone and FIG. 4 c is a front viewof the carrier alone. It can be seen that that carrier comprises twopairs of parallel, vertically extending walls 40 connected by atransverse bar 19. Each pair of parallel walls 40 is attached to a liftarm on a work machine and is formed from steel. The pairs of parallelwalls 40 are spaced from one another the same distance as the lift armsare spaced from one another. The parallel walls 40 include a pluralityof apertures which form attachment points for the tool and lift arms.Plates 41 and strengthening bars 42 are provided between the walls ofeach pair of walls to provide structural strength. Strengthening bars 42also function as dump stops for the carrier against the bottom of thelift arms.

A latching mechanism 46 is provided that extends between the two pairsof parallel walls 40. The latching mechanism will be described in moredetail below.

The lift arms are attached to the carrier using pin or bearing thatextends through apertures 16 in the carrier walls and through acorresponding passage or aperture in the end of the lift arms 11. A 45mm diameter steel cylindrical pin and circular apertures are used toallow the carrier and/or lift arms to pivot about the pin.

The lift arms are also connected to the carrier by a similar pinnedarrangement at the attachment points 17. This arrangement allows thecarrier to be tilted relative to the lift arms using a hydraulic piston,as described in U.S. Pat. No. 7,001,137.

It should be noted that each lift arm in use, defines a vertical planeof movement, parallel to the plane of the paper in FIG. 1, and that thevertical plane defined by each lift arm passes between and is parallelto each of the corresponding pairs of parallel walls of the carrier.

With reference to FIGS. 3, 4 a, 4 b, 4 c, and 5 the manner in which thecarrier is attached to the bucket will now be described.

The bucket includes four hooks 18 that engage the transverse bar 19 onthe top of the carrier 12. The transverse bar is a 50 mm diameter steelrod. As shown, the hooks are symmetrically disposed on either side ofeach pair of upright walls 40. The bucket 10 also has two latch brackets30, shown in FIG. 5, on the lower end, to which the carrier attachesusing the latching bar of the latching mechanism 46. The latch brackets30 each have an aperture extending through them defining a transversebore through which the latching bar, or a pin attached to the latchingbar, extends when the carrier is locked to the bucket. The latchbrackets 30 simply consist of protrusions with an aperture through them.

The latch brackets 30 on the bucket 10 extend into a space formed in thecontact pads 43 on the lower front face of the carrier 10, as shown inFIG. 4 a. The contact pads 43 are positioned at the bottom of thecarrier 12 and extend between each pair of double walls 40. The contactpads have a flat front face that in use contacts the bucket or othertool attached to the carrier. The flat front face is the surface throughwhich force from the lift arm or work machine is applied to the toolduring a pushing or lifting operation. The contact surface of thecontact pads lie substantially in line with the vertical plane definedby the lift arms, i.e. between the corresponding upright walls 40, andare symmetrical about a vertical centre line, as can be clearly seen inFIG. 4 c. The largest forces that are applied by the work machinethrough the lift arms are typically when the work machine is performinga pushing operation by driving forward or through a lifting action ofthe lift arm. By having the contact pads in line with the lift arms andhaving the tool attachment points within the contact pads, stress on thecarrier is minimized. There are no bending forces or transverse loadsapplied to the carrier 12 because the lift arms 11 are directly in linewith the contact surface and attachment points between the carrier 12and the tool 10. The carrier 12 acts only to provide releasableconnection between the lift arms and the tool.

It is possible to provide symmetrically disposed tool attachment pointsoutside of the contact pads, but having the tool attachment pointswithin the same vertical plane as the contact pads and the lift arms isthe preferred arrangement as it provides the greatest durability for agiven amount material, e.g. for a given thickness of the carrier walls.Other possible variations include providing the tool attachment pointsin line with the lift arms but contact pads disposed, preferablysymmetrically, on either side of the tool attachment points in atransverse direction.

The contact pads 43 in the embodiment FIGS. 4 a, 4 b and 4 c are formedfrom cast steel and are welded to the upright walls. However, they maybe integrally formed with the walls or attached in some other suitableway such as brazing, using an epoxy, or mechanical fasteners such asbolts or rivets. The contact pads are symmetrical, so a single designcan be used for both sides of the carrier.

As described, within the front face of each contact pad 43 a recess 44is formed to receive the latch brackets 30 on a tool. Each contact padincludes a bore defined by apertures 45 that align with the apertureformed in the corresponding latch bracket 30 on the tool so that whenthe contact pad is correctly positioned in contact with the tool, theapertures 45 in the contact pad align with the aperture in the latchbracket and the transverse locking bars of the latching mechanism 46 canpass through all of the apertures to fix the tool to the carrier.

The latching mechanism is similar to that described in U.S. Pat. No.7,001,137 and will now be briefly described. The latching mechanismoperates to attach the carrier to the tool at the tool attachment pointswithin both contact pads and may be operated to latch and unlatch thetool from one side of the carrier. The latching mechanism comprisessteel locking bars that extend through the bore in each contact pad whenin a locked position. A handle 47 is attached to the locking bars toallow a user to move the locking bars between locked and unlockedpositions. A long locking bar 49 extends from the handle through a firstpair of upright walls 40 to the bore in the contact pad on the otherpair of upright walls. A short locking bar 50, comprising a 30 mmdiameter pin is attached to the handle 47 by a linking arm 48 andextends through the bore in the contact pad 43 on the first pair ofupright walls. The long locking bar as shown is formed in three parts. Astraight section attached to the handle 47 is joined to a dog-leggedsection using bolts. On the end of the dog-legged section is a 30 mmdiameter pin that extends into the bore formed in the contact pad.

The long locking bar 49 includes a washer 53 stopped by a cross boltextending through the bar. A helical spring 52 is positioned between thewasher and the first set of upright walls 40 to bias the locking barsinto a locked position.

The locking bars are moved to an unlocked position by a user pulling thehandle against the bias of the spring. In the unlocked position, thelocking bars are pulled out of engagement with the latch brackets on thebucket. The bucket can then be simply disengaged from the carrier bymoving the carrier downwards and out of engagement with hooks 18. Thesame process can be carried out in reverse to attach and lock a tool tothe carrier.

A retaining bracket 51 is provide to retain and support the long lockingbar 49 in alignment with the apertures in the contact pad 43 when in theunlocked position.

The retaining bracket is formed from steel and is welded to one of theupright walls 40.

Advantageously, the locking bars can be held in an unlocked position.For example, the mechanism described in U.S. Pat. No. 7,001,1137 or U.S.Pat. No. 5,466,13, the contents of which are incorporated herein byreference, may be used.

An automated mechanism for operating the latching mechanism may beprovided, as described, for example, in U.S. Pat. No. 7,001,137.

Having described the preferred embodiment, it will become apparent thatvarious modifications can be made without departing from the scope ofthe invention as defined in the accompanying claims.

1. A combination including a lift arm, a tool and a carrier, the carriercoupled to the lift arm and the tool for releasably attaching the toolto the lift arm, the carrier comprising: a lift arm attachment point forattachment to the lift arm; a tool attachment point for releasableattachment to the tool; and a contact pad for contacting the tool inuse; wherein, in use, the lift arm and contact pad lie in the samevertical plane.
 2. The combination of claim 1, wherein the toolattachment point lies in the vertical plane.
 3. The combination of claim1, wherein the lift arm attachment point lies in the vertical plane. 4.The combination of claim 1, wherein the tool attachment point is a partof the contact pad.
 5. The combination of claim 1, wherein the toolattachment point comprises an aperture in the contact pad.
 6. Thecombination according to claim 1, wherein the carrier comprises rightand left lift arm attachment points, spaced from one another in ahorizontal direction, for attachment to the lift arms of a work machine;and, right and left contact pads for contacting the tool in use;wherein, in use, the right lift arm attachment point and right contactpad lie in a first vertical plane and the left lift arm attachment pointand left contact pad lie in a second vertical plane.
 7. The combinationaccording to claim 6, wherein the carrier further comprises right andleft pairs of upright walls, and a transverse member connecting theright and left pairs of upright walls, wherein the right contact pad ispositioned between the right pair of upright walls and left contact padis positioned between the left pair of upright walls.
 8. The combinationaccording claim 7, wherein the right lift arm attachment point ispositioned between the right pair of upright walls and left lift armattachment point is positioned between the left pair of upright walls.9. A carrier for attaching a tool to a pair of lift arms of a workmachine, comprising: right and left lift arm attachment points, spacedfrom one another in a transverse direction, for attachment to the liftarms of a work machine; a first tool attachment point for releasableattachment of the tool to the carrier; right and left contact pads, forcontacting the tool in use; wherein the right lift arm attachment pointand right contact pad lie in a first plane perpendicular to thetransverse direction and the left lift arm attachment point and leftcontact pad lie in a second plane perpendicular to the transversedirection.
 10. The carrier of claim 9, further comprising a second toolattachment point, wherein the first tool attachment point lies in thefirst plane and the second tool attachment point lies in the secondplane.
 11. The carrier of claim 10, wherein the first tool attachmentpoint is a part of the right contact pad and the second tool attachmentpoint is part of the left contact pad.
 12. The carrier of claim 11,wherein the first tool attachment point comprises an aperture in theright contact pad.
 13. The carrier of claim 9, further comprising rightand left pairs of upright walls, and a transverse member connecting theright and left pairs of upright walls, wherein the right contact pad ispositioned between the right pair of upright walls and left contact padis positioned between the left pair of upright walls.
 14. The carrier ofclaim 13, wherein the right lift arm attachment point is positionedbetween the right pair of upright walls and left lift arm attachmentpoint is positioned between the left pair of upright walls.
 15. Thecarrier of claim 9, further comprising a fastener for releasablysecuring the tool to the carrier at the tool attachment points.
 16. Thecarrier of claim 15, wherein the fastener comprises bars that extendthrough apertures formed in each of the contact pads.
 17. The carrier ofclaim 16, wherein the fastener comprises a handle that is operable todisengage the fastener from both attachment points.
 18. The carrier ofclaim 9, wherein the lift arm attachment points allow for pivotalmovement of the carrier relative to the lift arms about a transverseaxis.
 19. A combination including a lift arm, a tool and a carrier, thecarrier coupled to the lift arm and the tool for releasably attachingthe tool to the lift arm, the carrier comprising: a lift arm attachmentpoint for attachment to the lift arm; a tool attachment point forreleasable attachment to the tool; and, wherein, in use, the lift armand tool attachment point lie in the same vertical plane.
 20. A carrierfor attaching a tool to a pair of lift arms of a work machine,comprising: right and left lift arm attachment points, spaced from oneanother in a transverse direction, for attachment to the lift arms of awork machine; right and left tool attachment points for releasableattachment of the tool to the carrier; wherein the right lift armattachment point and right tool attachment points lie in a first planeperpendicular to the transverse direction and the left lift armattachment point and left tool attachment point lie in a second planeperpendicular to the transverse direction.